The present invention, belonging to the field of multiphase flow metering, relates to an apparatus for measuring flow rates of individual phases of a gas/liquid multiphase flow typically such as an oil/gas water three phase flow in oil and gas industry.
Multiphase flow metering has been regarded as one of the critical technologies to determine the success of oil and gas industry in the future. Great advances have been made in RandD of multiphase flow metering over the recent years, but most of prior-art multiphase flow metering over the recent years, but most of prior-art multiphase flow meters are able to measure only one or a small number of flow patterns due to the complexity and stochastic process of the multiphase flow. Therefore, one of the technical difficulties in the field of multiphase flow metering is how to effectively condition and control flow patterns of the multiphase flow. Referring to the prior-art technologies, one example is disclosed in Chinese Patent No. ZL 97229522.4 that provides a technical solution for conditioning flow patterns and measuring flow rates of the gas/liquid multiphase flow. Products based on the above-mentioned patent have also been extensively used in oil and gas production procedure in some onshore oilfields. However, the above-mentioned apparatus comprises some moving components and is not suitable for un-manned applications in offshore, desert, and marginal fields. For these un-manned applications reliability of the apparatus is more important than any other technical requirements, and it is the first factor considered by the users. Thus RandD for multiphase flow metering technologies without moving components and applicable for various flow patterns is currently one of the most important challenges in the field of multiphase flow technology.
The object of the present invention is to provide a multiphase flow metering apparatus that is suitable for unmanned application.
For achieving the above-mentioned object the present invention provides an apparatus for measuring flow rates of individual phases of the multiphase flow, mounted on a flow pipe, comprising: static means for generating slug flow and a cross correlation type flow meter successively mounted on said flow pipe; means for conditioning multiphase flow and means for measuring phase fractions of multiphase flow successively mounted on said flow pipe; wherein said means for conditioning multiphase flow locates downstream of said cross correlation type flow meter, or said means for measuring phase fractions locates upstream of said static means for generating slug flow; and data acquisition and processing means for collecting dada from said cross correlation type flow meter and said means for measuring phase fractions and carrying out calculation of flow rates of individual phases of the multiphase flow.
Additionally, the apparatus may also comprise a throttle type flow meter located downstream of said means for conditioning multiphase flow and adjacent to said means for measuring phase fractions, and a device for measuring temperature and a device for measuring pressure separately mounted on said flow pipe.
Features of the apparatus according to the present invention include compact structure, less pressure loss, and especially without moving components so as to prevent the apparatus itself from mechanical troubles. The apparatus can operate reliably over a long period of time thus being suitable for un-manned applications in the offshore, desert, and marginal fields. Moreover, the apparatus is able to measure various multiphase flow patterns with high accuracy and wide operating envelope.